Stop-motion mechanisms for sewing machines



Oct. 25, 1955 M. F. IVANKO STOP-MOTION MECHANISMS FOR SEWING MACHINES 3 Sheets-Sheet 1 Filed Oct. 9, 1953 INVENTOR. Michael F lvcJnko BY a WITNESS m :2

ATTORNEY Oct. 25, 1955 Filed Oct. 9, 1953 M. F. IVANKO 2,721,526

STOP-MOTION MECHANISMS FOR SEWING MACHINES 5 Sheets-Sheet 2 INVENTOR. Fig.2. Michael Elvonko WITNESS BY I 01/ zdgm'mfiwm ATTORNEY I Oct. 25, 1955 F. IVANKO 2,721,526

STOP-MOTION MECHANISMS FOR SEWING MACHINES Filed Oct. 9, 1953 3 Sheets-Sheet 3 54 25 Fig.3. 9.5.

7 4K444 d 28 INVENTOR. Fig.6. Figt7. Fig.8. BY M|h 1 Elvonko WITNESS ATTORNEY United States Patent MECHANISMS FOR SEWING MACHINES ApplicationOctober 9, 1953, Serial No. 385,097

9 Claims. (Cl. 112-67) STOP-MOTION The present invention relates to sewing machines and particularly tacking machines wherein there is employed a stop-motion mechanism that brings the machine to rest in a definite stop-position upon the completion of each cycle of actuation, or in other words, upon the completion of each tack. The primary object of the present invention is to provide an improved stop-motion mechanism for sewingmachines that is more economical and durable and more dependable and eflicient in operation.

Having in mind the above and other objects that will be evident from an understanding of this disclosure, the invention comprises the device's, combinations and arrangements of parts as illustrated in a preferred embodi ment of the invention which is hereinafter set forth in such detail as to enable those skilled in the art readily to understand the function, operation, construction and advantages of it when read in conjunction with the accompanying drawings in which:

Fig. l is a side elevation of a sewing machine embodying the present invention.

Fig. 2 is a fragmentary end elevation on an enlarged scale of the sewing machine illustrated in Fig. l, with parts broken away and some of the parts that would normally appear being omitted to illustrate more clearly the invention.

Fig. 3 is a fragmentary sectional view taken substantially on the line 33 of Fig. 2 and illustrating only the stop-motion mechanism and the adjacent portions of the machine.

Fig. 4 is afragmentary detail sectional view taken substantially on the line 4-4 of Fig. 2.

Fig. 5 is a fragmentary detail sectional view taken substantially on the line 55 of Fig. 2.

' Figs. 6, 7 and 8 are detail views illustrating the relation between the belt and the separable pulley faces in positions of running, idling and stop respectively.

' Fig. 9 is a fragmentary detail view in elevation of the stop-cam carried by the actuating shaft.

The present invention is herein illustrated as embodied in a well-known tacking machine of the type disclosed in the patent of Horton, No. 1,051,998, to which reference may be had for a more complete description of the machine mechanisms and the operation thereof. The machine is hereinafter only briefly described to form a background for the present invention.

As illustrated, the disclosed machine includes a base 1", a work-arm 2 extending laterally from the base, a standard 3 surmounting the base and a bracket-arm 4 carried by the standard. The bracket-arm 4 terminates in a hollow head 5 in which there is journaled for vertical reciprocation a needle-bar 6 carrying a needle 7 at its lower end. In the usual manner, the needle 7 is adapted to cooperate with an oscillating shuttle (not shown) carried by the work-arm 2 in the formation of lock-stitches.

The work is fed relative to the stitching mechanism by a clamp-feed mechanism comprising a feed-bar 8 terminating in a feed-plate 9 that rests upon and slides relative to the upper surface of the work-arm 2. The work is clamped against the feed-plate 9 by a clamp 10 carried by a bracket 11 that is also mounted upon the feed-bar 8. The clamp 10 is spring-biased downwardly and is adapted to be raised by means of an arm 12 that engages under and raises clamp-lifting pins 13 secured to the clamp 10. The arm 12 is carried at the lower end of a clamp-bar 14 journaled for longitudinal sliding movement in the head 5 and fastened at its upper end to one end of a lever 15 that is pivoted at 16 intermediate its ends to the bracket-arm 4. A chain 17 is secured to the other end of the lever 15, which chain is to be connected in the usual fashion to an actuator, such as a foot-treadle (not shown). Thus, when a pull is exerted on the chain 17, the lever 15 is pivoted which raises the clamp-bar 14 and consequently the clamp 10.

Feed-motions defining the desired stitching pattern or tack are imparted to the feed-bar 8 by appropriate connections with a rotary pattern cam 18 journaled upon an axis 19 transversely of the standard 3. Other appropriate mechanism such as a thread-nipper and threadcutter are also actuated in timed relation in the stitching cycle by the cam 18.

In the usual manner, actuation is imparted to the various mechanisms of the sewing machine including the cam 18 by a main or bracket-arm shaft 20 that is journaled longitudinally of the bracket-arm 4 and extending externally of the frame at the end thereof. Mounted upon the end of the shaft 20 is a sleeve 21 keyed to the shaft 20 by pins 22. The sleeve 21 is part of a fast pulley element 23 which further comprises a flange 24 integral therewith and provided with a belt-engaging face 25 that forms the first side of a V-belt groove. Complemental to the fast pulley element 23 is a loose pulley element 26 provided with a hub-portion 27 journaled upon the sleeve 21 for rotation and axial sliding relative thereto, and a flange 28 that carries belt-engaging faces 29 and 30 which form the bottom and second side of a V-belt groove. The bottom belt-engaging face 30 is designed to be telescopically received within a cupshaped recess formed in the fast pulley element to provide for sliding of the face 29 toward and from the face 25. A conventional V-belt 31 is entrained about the pulley comprising the elements 23 and 26, and is seated in the groove defined by the belt-engaging faces 25, 29 and 30. The belt 31 is adapted to be connected to any suitable source of power (not shown) for driving the machine.

Outward sliding movement of the loose pulley element 26 relative to the sleeve 21 is limited by a resilient snap-ring 32 that is seated in a peripheral groove in the sleeve 21 and against which the hub-portion 27 of the pulleyelement abuts. A coiled compression spring 33 is positioned about the hub 27 and sleeve 21, and between the inner faces of the two pulley elements to urge the pulley element 26 outwardly. To provide for sliding manually the pulley element 26 toward the element 23, there is provided a circular cap 34 having a lateral reduced diameter rim 35, the outer surface of which forms a tight fit with and thus is frictionally held within the inner cylindrical surface of an axially-extending annular boss 36. A hardened bearing-ball 37 is embedded centrally of the cap 34 and is adapted to be engaged and moved axially by an arm 38 which is hereinafter more fully described. A hardened wear-plate 39 is carried by the arm 38 at the point of contact with the bearing-ball 37.

It is customary to provide a continuously acting drive means for sewing machines to which the machine may be selectively clutched. Thus, the belt 31 is designed to be constantly driven and to be clutched to the main shaft 20 by the two-part separable pulley comprising the pulley elements 23 and 26. It will be seen that, when the loose pulley element 26' is spaced from the fast pulley element 23 a distance such that the belt-engaging faces and 29 thereof are spaced a distance greater than the width of the belt 31, the belt will run on the cylindrical bottom face 30 of the loose pulley element 26 which will thus rotate freely with respect to the fast pulley element. However, when the element 26 is shifted toward the element 23, the belt 31 will be clamped between the faces 25 and 29 and out of contact with the face 30, as seen in in Fig. 6. In this condition, the side. of the belt 31 in engagement with the face 25 of the element 23 will frictionally engage the face 25 and will thus rotate the same, therewith, and since the pulley element 23 is fast on the shaft 20, the machine will be actuated. In this manner, by axially sliding the loose pulley element, the drive means can be clutched to and declutched from the machine-actuating main-shaft 20.

Secured to the end portion of the standard 2 is a bracket having a pair of opposed lugs 41 which carry a pivot-pin 42. Journaled on the pivot-pin 42 is a lever 43 having a strap portion 44 that encircles the sleeve 21. A stop-dog 45 includes a lateral stop-arm 46 extending radially of the shaft 20 and a strap portion 46a that loosely embraces the sleeve 21 and is interposed between the sleeve 21 and strap 44. The stop-dog is held against axial sliding movement with respect to the strap 44 by a pair of resilient snap-rings 47. The free end of the stoparm 46 is pivotally connected at 48 to a vertically disposed spring-rod 49 which freely extends through a stationary member in the form of a bushing 50 that includes a shank 51, see Fig. 3, secured by a screw 52 to an arm 53 integral with and extending laterally from the lever 43 A pair of opposed neutralizing compression springs 54 and 55 encircle the rod 49, one arranged on either side of the bushing 50. The spring 54 abuts at one end against the enlarged head of the rod 49 and at the other end against the bushing 50, while the spring 55 abuts at one end; against the bushing 50 and at the other end against a pair of stop-nuts 56 at the free end of the rod 49. Thus, any movement of the rod 49 in either direction will be spring resisted, whereby the rod will be. resiliently centered.

. The stop mechanism includes a stop-cam 57 of the facecam type formed on the inner side of the flange 24 of the. fast pulley element 23, which cam presents a smooth continuous substantially annular end face axially thereof. The cam 57 is designed to cooperate with the arm 46 of the, stop-dog 45 and is therefore provided with a stopshoulder- 57a, see Fig. 9, which in the disclosed embodi.

ment comprises one side wall of a recess 58in the annular end face, which recess is adapted to receive the stop-arm 46. The cam 57. presents a, smooth butaxially decreasing s l i ace in the direction of rotation toward the recess 58 so that; the arm 46v will be led into the recess orinto abutment with the stop-shoulder 5711- when the stop mechanism has been thrown-in. It will, of course, be understood that a stop-shoulder alone without the recess would be adequate and that the present disclosure relates only to a preferred embodiment. In the following claims the term stop-shoulder is intended to generically include any abutment surface that operatively contacts the arm of the stop-dog. When the mach-inc is to be stopped, the lever 43 is shifted so that the lateral arm 46' will engage the surface of the cam 57' on the pulley element 23, and as soon as the stop-shoulder 57a and the recess 58 in the cam comes around, the stop-arm 46 will abut against the shoulder'and fall into the recess. The lateral stop-arm 46 is capable only of rotation about the shaft 20, which rotation is resisted by the springs 54 and 55. When the arm 46, is engaged by thestop-shoulder 5741,, the momentum of the moving parts of the machine acts to depressthe free end of the same against the action ofspring 54, thereby absorbing the energy in the moving parts; The

springs 54 and 55 thereafter coact to center the lateral 'arm 46.

The lever 43 is biased by a spring 59 into stop-position, which spring is normally compressed between the bracket 40 and the lever 43 at a point intermediate the ends of the lever. To retract the mechanism from stop-position there is provided an actuating bell-crank lever 60 pivoted by a pin 61 to a pair of opposed lugs 62 integral with the bracket 40. The lever 60 comprises a first arm 63 having a pull-chain 64 secured to the end thereof. In the usual manner, the pull-chain 64 is connected to suitable means, whereby the operator may conveniently actuate the same, such as a foot treadle (not shown). The lever 60 also includes a second arm 65 whichis formed as a cam and engages the lever 43, whereby when the bell-crank lever 60 is rotated about the pin 61 by a pull on the arm 63, the arm 65 will force the lever 43 about its pivot 42 against the action of spring 59 away from stop-position.

When the stop mechanism is withdrawn from stopposition by a pull exerted upon the chain 64, the operation of the machine is automatically initiated by the arm 38 which forces the loose pulley element 26 toward the fast pulley element 23 and thus clutches the belt 31 to-the fast pulley element as hereinbefore described. The arm 38 is formed, as illustrated in Fig. 3, with a portion 66 that is arranged at a right angle to the portion carrying the wear plate 39, which portion 66 extends through an aperture in the lever 43 and is secured therein by a set screw 67, whereby the arm 38 iscarried by the lever 43. Thus, when the lever 43 is moved about its pivot 42, the arm 38 is also swung to engage or release the clutching mechanism.

Means are provided for automatically releasing the clutch mechanism a predetermined number of stitches prior to termination of the stitching cycle, and for automatically actuating the stop mechanism upon termination of the stitching cycle. This means comprises a latch 68 pivoted intermediate its ends by a pivot-screw 69 to an upper surface of the bracket 40. The latch 68 in: cludes a first arm 70 and a second arm 71 extending in opposite directions from the upper and lower ends respectively of a hub. portion about which is coiled a torsion spring 72. The one end of the spring 72 is secured by a screw 73 to the arm 70- of the latch 68 and the opposite end bears against a wall of the standard 3, as best seen in Fig. 4, whereby the latch 68 will be biased to urge the arm 70 toward the lever 43,01 in the direction of the arrow A.

The arm 70 of the latch 68 terminates in a pair of stepped detents 74 and 75 which areadapted to engage a wear-plate 76 secured to the lever 43- by a, screw 77 and thereby hold the lever against the action of the-spring, 59, the spring 72 urging the detent-carrying end of the arm 70 toward thelever 43. The arm 71 of the latch, 68 terminates in a beveled end that is adapted to be engaged by a pair of cams 79 and 80 that are secured tov the rotary cam 18 by screws 81 and 82 respectively, The cam 80. is so positioned on the rotary cam 18 that it will contact the end 78 of the arm 71 a predetermined number of stitches, for example three stitches, before the end of the stitching cycle, and it is so dimensioned thatv it, will move the latch 68 enough to release the lever 43 from the detent 75 but not enough to release itfrom the detent 74. The lever 43 will then be moved by thev spring 59 a relatively short distance toward, stop-position, which distance is made adequate to release the driving connection between the belt and the separable pulley elements 23. and 26. but not adequate to bring the stop mechanism into operation, or in other words, to bring the lateral arm 46 0f the stop-dog 45 into the, path of the stop-shoulder 57a of the cam 57 on the fast pulley element 23. The driving connection between the belt 31 and the fast pulley element 23 will therefore be broken, as illustrated in Fig. 7" in. which the belt will ride idly on the cylindrical bottom face of the loose pulley element 26. The machine will then coast through the remainder of the stitching cycle.

The cam 79 is so positioned on the rotary cam 18 that it will contact the end 78 of the arm 71 at the beginning of the last stitch in the stitching cycle, and is so dimensioned that it will move the latch 68 enough to release the lever 43 from the detent '74 of the arm 70 and thus completely release the lever 43 which is then moved toward stop-position by the spring 59. The clutching mechanism is also then completely released and will move to its end position as illustrated in Fig. 8. When the lever 43 is in stop-position, the lateral arm 46 of the stop-dog is positioned in the path of travel of the stopshoulder 57a of the face-cam 57 and will be engaged by the same as it comes around, thus stopping the machine. It should be noted that when the machine finally comes to rest, the cam 79 has been rotated beyond its point of contact with the end 78 of the latch-arm 71.

To again initiate operation of the machine, a pull on the chain 64 will pivot the bell-crank lever 60 about the pin 61 causing the arm 65 thereof to force the lever 43 about its pivot 42 away from stop-position against the action of spring 59. As the lever 43 is thus retracted, which withdraws the lateral arm 46 from engagement with the cam 57 on the fast pulley element 23, the latch 68 will be pivoted under the action of the spring 72 to place the detents 74 and 75 in front of the same so that when the pull on the chain 64 is relaxed, the lever will be held in operative or running position by the detent 75 until again automatically released at the end of the cycle. As hereinbefore pointed out, moving the lever 43 also acts to automatically clutch and declutch the driving connections comprising the belt 31 and the pulley element 23.

Numerous alterations of the structure herein disclosed will suggest themselves to those skilled in the art. However, it is to be understood that the present disclosure relates to a preferred embodiment of my invention which is for purposes of illustration only and not to be construed as a limitation of the invention. All such modifications which do not depart from the spirit of the invention are intended to be included within the scope of the appended claims.

Having thus set forth the nature of the invention, what I claim herein is:

1. In a sewing machine having a frame and a rotary shaft journaled in said frame, a stop-motion mechanism for said shaft comprising a stop-dog in sliding and bearing engagement with said shaft and having an arm extending substantially radially with respect to said shaft, an element fixed to said shaft for rotation therewith, a stop-shoulder on said element arranged axially of said shaft and spaced radially from the axis of said shaft, a stop-rod fastened to said arm at a point radiaily outward of said stopshoulder, spring means associated with said rod for resisting longitudinal motion of the same, and means for moving said stop-dog into and out of the path of rotation of said stop-shoulder.

2. In a sewing machine having a frame and a rotary shaft journaled in said frame, a stop-motion mechanism for said shaft comprising a stop-dog embracing said shaft and having an arm extending substantially radially with respect to said shaft, an element fixed to said shaft, a smooth continuous surface formed on said element axially of said shaft and a recess formed in said surface, said surface being spaced radially from the axis of said shaft and the recess in said surface being formed to receive said arm axially of said shaft, a stop-rod pivoted to said arm at a point radially outward of said surface, spring means associated with said stop-rod for resiliently resisting longitudinal motion of the same, and means for moving said stop-dog toward and from engagement with the annular surface of said element.

3. In a sewing machine having a frame and a rotary 6. shaft journaled in said frame, a stop-motion mechanism for said shaft comprising a stop-dog engaging and slidable axially of said shaft and having an arm extending substantially radially with respect to said shaft, a face cam having a stop-shoulder fixed to said shaft for rotation therewith, a stop-rod pivoted to said arm at a point radially outward of said stop-shoulder, spring means associated with said rod for resisting longitudinal motion of the same, and means for sliding said stop-dog on said shaft to move said arm into and out of the path of rotation of said stop-shoulder.

4. In a sewing machine having a frame and a rotary shaft journaled in said frame, a stop-motion mechanism for said shaft comprising a stop-dog in sliding and bearing engagement with said shaft and having an arm extending substantially radially with respect to said shaft, an element fixed to said shaft for rotation therewith, a stop-shoulder on said element arranged axially of said shaft and spaced radially from the axis of said shaft, a stop-rod fastened to said arm at a point radially outward of said stop-shoulder, spring means associated with said rod for resisting longitudinal motion of the same, spring means for resiliently urging said stop-dog into engagcment with the surface of said element and manual means for retracting said stop-dog from engagement therewith, a latch for holding said stop-dog in retracted position, and means responsive to a predetermined number of revolutions of said shaft for automatically releasing said latch.

5. In a sewing machine having a frame and a rotary shaft journaled in said frame, a stop-motion mechanism for said shaft comprising a lever pivotally carried by said frame on an axis arranged substantially perpendicular to the axis of said shaft, a stop-dog carried by said lever for rotation relative thereto, said stop-dog slidably embracing said shaft, an arm on said stopdog extending radially with respect to said shaft, an element having a face-cam comprising a smooth continuous cam surface and having a stop-shoulder, said element being fixed to said shaft with the face-cam arranged axially of said shaft, a stop-rod pivoted to said arm at a point radially outwardly of said cam surface, a stationary member carried by said frame, oppositely acting springs arranged between said stationary member and the opposite ends of said stop-rod for resiliently centering the same longitudinally, a spring arranged between said frame and said lever for urging the lever in that direction in which the arm is in operative engagement with said face-cam, man ual means for urging said lever in the opposite direction, latch means for holding said lever against the action of the spring with said arm out of operative engagement with said face-cam, and means responsive to a predetermined number of revolutions of said shaft for automatically releasing said latch.

6. In a sewing machine having a frame, a rotary shaft journaled in said frame, driving means for said shaft, clutching mechanism for operatively connecting said driving means in driving relation to said shaft, a stop-motion mechanism for said shaft comprising a stop-dog in sliding and bearing engagement with said shaft and having an arm extending substantially radially with respect to said shaft, an element fixed to said shaft for rotation therewith, a stop-shoulder on said element and spaced radially from the axis of said shaft, a stop-rod pivoted to said arm at a point radially outward of said stopshoulder, spring means associated with said rod for resisting longitudinal motion of the same, means for actuating and de-actuating said clutching mechanism, means for moving said stop-dog into and out of stop-position in the path of rotation of said stop-shoulder, means for simultaneously actuating said clutching mechanism and moving said stop-dog out of stop-position, and automatic means responsive to a predetermined number of revolutions of said shaft for deactuating said clutching mechanism and subsequently, after a predetermined number of revolutions of said shaft, for moving saidstop-dog into stop-position.

7. In a sewing machine having a frame, a rotary shaft journaled-in said frame, a belt pulley comprising a fast pulley element fixed to said shaft and a loose pulley element' carried by said shaft for rotation and translation relative thereto, a lever pivotally carried by said frame, operative connections between said lever and said loose pulley element for sliding the latter longitudinally of said shaft upon. pivotal movement of said lever, a stop dog carried by said lever and having a lateral arm, a stoprod connected to said arm, resilient means resisting longitudinal motion of said stop-rod, said fast pulley element being provided with a smooth annular surface having a stop-shoulder receiving said arm, spring means pivotally biasing said lever in that direction in which said loosepull'ey element is moved axially on said shaft away from said fast pulley element and said arm is moved toward operative engagement with the annular surface of said fast pulley element, and manual means for pivoting the lever in the opposite direction against the action of the spring, latch means for holding said lever against the action of the spring, and means responsive to a predetermined number of revolutions of said shaft for automatically releasing said latch.

8. In a sewing machine having a frame, a rotary shaft journaled in said frame, a feed-cam journaled in said frame, operative connections between said feed-cam and said shaft to drive the former in response to actuation of the shaft, a belt-pulley comprising a fast pulley element fixed to said shaft and a loose pulley element carried by said shaft for rotation and translation relative thereto, a lever pivotally carried by said frame, operative connections between said lever and said loose pulley element for sliding the latter upon pivotal movement of said lever, a stop-dog carried by said lever and having a lateral arm, a stop-rod connected to said arm, resilient means resisting motion of said stop-rod under the action of said arm, said fast pulley element being provided with a smooth annular surface having a recess designed to receive said arm, spring means pivotally biasing said lever in that direction in which said loose pulley element is moved axially on said shaft away from said fast pulley element and said arm is moved toward operative'engagement with said annular surface of said fast pulley element, manual means for pivoting said lever in the opposite direction against the action of said spring means, a latch pivoted to said frame with a first end adjacent said lever and a second end adjacent said feed-cam, the first end of said latch cooperating with the lever to hold the same against the action of said spring in two separate latching positions including a first position in which said loose pulley element is urged toward said fast pulley element, and means on said feed-cam acting upon the second end of said latch for progressively pivoting said latch and releasing said lever successively from latching positions.

9.In a sewing machine having a frame, a rotary shaft journaled on said frame, a clutching mechanism comprising a belt-pulley having a fast pulley element fixed to said shaft and a cooperating loose pulley element journaled on said shaft for rotation and translation relative thereto, a stop-motion mechanism for said shaft comprising an element having a stop-shoulder fixed to said shaft for rotation therewith, a stop-dog slidably bearing against said shaft and having an arm extending substanti-ally radially therefrom, means for resiliently resisting motion of said arm about'said shaft, a common actuator for sliding said loose pulley relative to said fast pulley element and for moving said arm into and out of stopposition in which said arm is in the path of rotation of said stop-shoulder, means for moving said actuator in one direction to slide said loose pulley element toward said fast pulley element and to move said arm out of stopposition, and automatic means responsive to a predetermined number of revolutions of said shaft for moving said actuator in the opposite direction to slide said loose pulley element away from said fast pulley element and, after a further predetermined number of revolutions of said shaft, to move said arm into stop-position.

References Cited in the file of this patent UNITED STATES PATENTS 575,965 Mack Jan. 26, 1897 2,277,475 Bilger Mar. 24, 1942 2,612,127 Hayes Sept. 30, 1952 

